2.8. Transmission Electron Microscopy
Samples were fixed with 2.5% glutaraldehyde and 1% osmic acid
overnight at 4°C for 1.5 h and then washed with phosphate-buffered
saline (PBS) thrice for 15 min. The samples were dehydrated with
different concentrations of gradient ethanol (30%, 50%, 70%, 80%,
90%, 95%, and 100%) and then embedded in a mixture of embedding agent
and acetone at 70°C overnight. Subsequently, 70 nm-thick sections were
obtained using a Reichert Jung ultrathin microtome and stained with lead
citrate and uranyl acetate. The sections were observed under an H-7650
transmission electron microscope.